RT Journal Article SR Electronic T1 Techniques for the rapid and sensitive detection of penicillinase JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 263 OP 267 DO 10.1136/jcp.16.3.263 VO 16 IS 3 A1 Holt, R. J. A1 Stewart, G. T. YR 1963 UL http://jcp.bmj.com/content/16/3/263.abstract AB Practical problems in the detection of penicillinase are discussed. A membrane technique for this purpose is described, with various modifications, suitable for screening large numbers of organisms and yet more sensitive than most methods. A one-stage membrane technique is adequate for detecting hydrolysis of penicillin G but a two-stage technique is required to demonstrate hydrolysis of some other penicillins. A gradient adaptation can be used for quantitative purposes. Staphylococci, coliforms, Proteus, and other organisms can be tested in this way for penicillinase formation; the method is also suitable for testing lysates, filtrates, and dialysates, provided independent provision is made for enzyme inducement.